Drill



July 1, 1969 Y P. usso 7 3,452,625

DRILL Filed Nov. 21. 1966 INVENTOR PETER Russo ATTORNEY St. Louis, Mo.63113 Filed Nov. 21, 1966, Ser. No. 595,919

Int. Cl. B23b 51/02 US. CI. 77-70 3 Clauns This invention relates ingeneral to cutting tools, and more particularly, to a drill of theso-called twist type having a novel cutting portion.

It is an object of the present invention to provide a drill having twincutting edges which are aligned transversely of the drill with anintervening U-shaped recess therebetween, providing a cutting portionwhich is relatively free of clogging during drilling operation.

It is another object of the present invention to provide a drill of thecharacter stated which is relatively easily ground; which is designed toprevent hanging up of the cut metal; and which, during usage,substantially prevents over-heating.

It is further object of the present invention to provide a drill of thecharacter stated, having a novel tip portion which efiects the drillingof frusto-conical holes in metallic sheet metal; which does not requirethe application of relatively great pressure for operation; and whichsubstantially eliminates burring.

It is an additional object of the present invention to provide a drillof the character stated which is strong and durable in usage; which byreason of its unique configuration is capable of usage for relativelylong periods of time without the necessity of sharpening; and which cutsrelatively rapidly.

Other objects and details of the invention will be apparent from thefollowing description, when read in connection with the accompanyingdrawings (1 sheet), wherein- FIGURE 1 is an end view of a drillconstructed in accordance with and embodying the present invention.

FIGURE 2 is a side elevational view of the tip portion of the drill.

FIGURE 3 is a vertical transverse sectional view taken on the line 3-3of FIGURE 2.

FIGURE 4 is an elevational view of the tip portion of the drill taken atan angle of 90 to the view thereof in FIGURE 2.

Referring now by reference characters to the drawing which illustratesthe preferred embodiment of the present invention, A generallydesignates a drill of the twist type incorporating a cylindrical body 1,having a tip portion 2 formed on one end thereof. Body 1 is providedwith at least 2 diametrally opposed flutes 3, 4 with a correspondingnumber of intervening lands 5, 6, the said flutes and lands being inconventional helical formation. The vallies of the flutes 3, 4 beingindicated 3', 4 respectively, constitute a part of the outer surface ofthe body portion. Body 1 may incorporate a smooth surface shank (notshown) in accordance with customary practice.

It is to be understood that drills having more than two flutes and twolands may be utilized in accordance with this invention, but two of eachhave been found preferable.

For orientation purposes, the term upwardly as used hereinbelowindicates the longitudinal direction toward tip portion 2 of drill A,while the term downwardly will be used to express the oppositelongitudinal direction, that away from said tip portion 2. The termoutwardly is used hereinbelow to indicate the direction radiallyoutwardly or away from the longitudinal axis of drill A, with the terminwardly used to designate the reverse direction, that being radiallytoward the longitudinal axis of said drill A.

United States Patent 3,452,625 Patented July 1, 1969 Tip portion 2 ofdrill A is of symmetrical configuration about a transverse lineindicated at XX, passing through the vallies 3', 4 of flutes 3, 4(FIGURE 1); it being understood that a plane passing through saidvallies would thus bi-sect drill A into two equal identical parts. Sincethe configuration of tip portion A on one side of line X-X is the sameas on the other side thereof, for purposes of simplification, thestructure on any one side thereof will be described, but with theunderstanding such description is equally applicable to such other side.In its upper terminal portion, land 5 is provided with a clearingsurface 7 of generally triangular character defined by a leading orcutting edge 8, an inner or trailing edge 9 substantially normal to saidcutting edge 8, and an outer arcuate peripheral edge 10. The point ofjuncture between cutting edge 8 and trailing edge 9 constitutes cuttingpoint or corner 11, with said cutting point 11 and cutting edge 8, beingin transverse alignment with the cutting point and cutting edge formedon land 6 as indicated respectively at 11' and 8'. Said cutting edges 8,8' together with the respective points 11, 11 are presented outwardly ofthe longitudinal axis of drill A or are laterally offset from deadcenter 12 of drill A. Trailing edges 9 of said lands 5, 6 constitute theupper limits of an upwardly opening recess 13 of general U-shapedconfiguration in cross-section (see FIGURE 2), with said dead center 12,being located at the base of said U-form. Said recess 13, which may bereadily formed by conventional grinding equipment incorporatesdownwardly and outwardly inclined portions 14, 14 formed in the upperportions of said lands 5, 6, respectively, adjacent the related trailingedge 9 to present secondary flutes. From the foregoing it will be seenthat tip portion 2 is of symmetrical nature having twin cutting edges 8,8' in transverse alignment which have trailing edges 9 which arepresented outwardly of dead center 12 of drill A, being separated by aU-shaped recess 13; said edges 9 incline outwardly, in oppositedirections, away from the center of drill A being in non-parallelrelationship. It will be seen that the clearing surfaces 7 are inclineddownwardly in opposite directions.

In operation, drill A is suited for drilling upon both sheet metal andrelatively thick metal stock; being supported by a guide, as customarywith jigs, to provide stability during usage. With drill A rotating inthe direction of the arr-ow as shown in FIGURE 1, the said drill islowered to the work with cutting points 11, 11', thus simultaneouslymaking initial contact with the surface of the work at two spaced sites.As drill A is rotated, the said cutting points 11, 11' will bite orotherwise cut into the work for introduction thereinto of cutting edges8, 8. The angle of slope of said cutting edges 8, 8 from theirrespective cutting points 11, 11' will cause a generally frustoconicalopening to be developed in the work by the drilling or cutting action ofsaid edges 8, 8', with the ultimate creation of an opening having itsside walls perpendicular to the plane of the surfaces of the work. Byreason of the unique generally U-shaped recess 13, cutting edges 8, 8'will effect, in sheet metal, the development of an integral Workfragment or plug, as it were, which may be bodily removed from the work,thereby preventing any clogging during the cutting action. With relativethin work pieces, there will, by reason of the unique, configuration oftip portion 2, be obviated the development of the customary chips andshavings as formed with drills known heretofore. Additionally, theprovision of the twin cutting edges will militate against thedevelopment of heat so that the drill may operate for relativelyextensive periods of time in a fully effective manner. With the twosharp cutting edges, 8, 8', the onset of dullness is relatively delayedso that said edges retain their cutting capability for relatively longperiods. The unique nature of said tip portion 2 eliminates the need forapplying substantial pressure during the cutting action as the said twincutting edges 8, 8' act in the manner of a double drill bit. With thepresent invention, each cutting edge cuts relatively less metal but yeteffects the total drilling procedure in a relatively rapid manner.

Drills formed in accordance with the present invention conduce to markedsimplicity in the grinding operation thereby assuring that the desiredconfiguration may be easily formed. It has been found that drills of thetype herein set forth have marked durability so as to obviate the needfor the frequency of grinding which has been encountered with drillsheretofore utilized. The slope of the sides of the U-shaped recess 13contributes substantially to the unusual properties of the presentdrill, rendering the same durable and resistant to dullness, as well aspreventive of early over-heaving.

The said cutting edges 8, 8', together with the intervening recess 13,may be formed on tip portion 2 by the usual stone grinding wheel, thetransverse extent of its peripheral face being slightly narrower thansaid recess 13.

It should be understood that changes and modifications in the formation,construction, arrangement, and combination of the several parts of thedrill may be made and substituted for these herein shown and describedwithout departing from the nature and principle of my invention.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. A drill comprising a cylindrical body having at least two flutes indiametrically opposed relationship and two intervening lands, saidflutes and lands being in helical formation, a tip portion provided onone end of said body, first and second cutting edges provided on saidtip portion and being in transverse alignment, first and second trailingedges, each trailing edge being substantially normal to the adjacentcutting edge and being in nonparallel relationship with each other, saidtip portion being symmetrically disposed about a plane passingtransversely therethrough between said cutting edges bisecting said tipportion into two identical components, each such component having aclearing surface formed at the end of the related land, said first andsecond cutting edges defining one margin of the related clearingsurface, said first and second trailing edges defining another margin ofthe related clearing surface, said clearing surfaces decliningdownwardly and outwardly from the junction between the related cuttingedge and trailing edge, said junction defining a cutting point, saidfirst second cutting edges being laterally offset with respect to thelongitudinal axis of said body, there being a U-shaped recess betweensaid cutting edges and transversely aligned therewith, said cuttingpoints defining the upper limit of said U-shaped recess, means definingrelatively short secondary flutes provided in the upper portion of eachof said lands adjacent the related trailing edge and constituting innerlateral portions of said U-shaped recess, said recess having a basebetween said secondary flutes extending linearly transversely of saidbody.

2. A drill as defined in claim 1 and further characterized by saidsecondary flutes having inclined portions extending radially downwardlyand outwardly of sad base.

3. A drill as defined in claim 2 and further characterized by said basebeing coincident with the dead center of said U-shaped portion.

References Cited UNITED STATES PATENTS 3,028,773 4/ 1962 Borneman 77702,334,089 1l/ 1943 Hallden 77-70 989,379 4/1911 Mather 77-70 FRANCIS S.HUSAR, Primary Examiner.

US. Cl. X.R. 117

1. A DRILL COMPRISING CYLINDRICAL BODY HAVING AT LEAST TWO FLUTES INDIAMETRICALLY OPPOSED RELATIONSHIP AND TWO INTERVENING LANDS, SAIDFLUTED AND LANDS BEING IN HELICAL FORMATION, A TIP PORTION PROVIDED ONONE END OF SAID BODY, FIRST AND SECOND CUTTING EDGES PROVIDED ON SAIDTIP PORTION AND BEING IN TRANSVERSE ALINGMENT, FIRST AND SECOND TRAILINGEDGES, EACH TRAILING EDGE BEING IN NONNORMAL TO THE ADJACENT CUTTINGEDGE AND BEING IN NONPARALLEL RELATIONSHIP WITH EACH OTHER, SAID TIPPORTION BEING SYMMETRICALLY DISPOSED ABOUT A PLANE PASSING TRANSVERSELYTHERETHROUGH BETWEEN SAID CUTTING EDGES BISECTING SAID TIP PORTION INTOTWO IDENTICAL COMPONENTS, EACH SUCH COMPONENT HAVING A CLEARING SURFACEFORMED AT THE END OF THE RELATED LAND, SAID FIRST AND SECOND CUTTINGEDGES DEFINING ONE MARGIN OF THE RELATED CLEARING SURFACE, SAID FIRSTAND SECOND TRAILING EDGES DEFINING ANOTHER MARGIN OF THE RALATEDCLEARING SURFACE, SAID CLEARING SURFACES DECLINING DOWNWARDLY ANDOUTWARDLY FROM THE JUNCTION BETWEEN THE RELATED CUTTING EDGE ANDTRAILING EDGE, SAID JUNCTION DEFINING A CUTTING POINT, SAID FIRST SECONDCUTTING EDGES BEING LATERALLY OFFSET WITH RESPECT TO THE LONGITUDINALAXIS OF SAID BODY, THERE BEING A U-SHAPED RECESS BETWEEN SAID CUTTINGEDGES AND TRANSVERSELY ALINGED THEREWITH, SAID CUTTING POINTS DEFININGTHE UPPER LIMIT OF SAID U-SHAPED SRECESS, MEANS DEFINING RELATIVELYSHORT SECONDARY FLUTES PROVIDED IN THE UPPER PORTION OF EACH OF SAIDLANDS ADJACENT THE RELATED TRAILING EDGE AND CONSTITUTING INNERLATERALPORTIONS OF SAID U-SHAPED RECESS, SAID RECESS HAVING A BASE BETWEEN SAIDSECONDARY FLUTES EXTENDING LINEARLY TRANSVERSELY OF SAID BODY.